2020-04-02 23:52:54

by Trond Myklebust

[permalink] [raw]
Subject: [PATCH 2/3] NFS/pnfs: Fix dereference of layout cred in pnfs_layoutcommit_inode()

From: Trond Myklebust <[email protected]>

Ensure that the dereference of the layout cred is atomic with the
stateid.

Signed-off-by: Trond Myklebust <[email protected]>
---
fs/nfs/pnfs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 6fcf26b16816..84029c9b2b1b 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -3137,10 +3137,10 @@ pnfs_layoutcommit_inode(struct inode *inode, bool sync)
end_pos = nfsi->layout->plh_lwb;

nfs4_stateid_copy(&data->args.stateid, &nfsi->layout->plh_stateid);
+ data->cred = get_cred(nfsi->layout->plh_lc_cred);
spin_unlock(&inode->i_lock);

data->args.inode = inode;
- data->cred = get_cred(nfsi->layout->plh_lc_cred);
nfs_fattr_init(&data->fattr);
data->args.bitmask = NFS_SERVER(inode)->cache_consistency_bitmask;
data->res.fattr = &data->fattr;
--
2.25.1


2020-04-02 23:52:54

by Trond Myklebust

[permalink] [raw]
Subject: [PATCH 3/3] NFS/pnfs: Reference the layout cred in pnfs_prepare_layoutreturn()

From: Trond Myklebust <[email protected]>

When we're sending a layoutreturn, ensure that we reference the
layout cred atomically with the copy of the stateid.

Signed-off-by: Trond Myklebust <[email protected]>
---
fs/nfs/nfs4proc.c | 1 +
fs/nfs/pnfs.c | 52 ++++++++++++++++++++++++++++++-----------------
2 files changed, 34 insertions(+), 19 deletions(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index e4f8311e506c..99e9f2ee7e7a 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -9297,6 +9297,7 @@ static void nfs4_layoutreturn_release(void *calldata)
lrp->ld_private.ops->free(&lrp->ld_private);
pnfs_put_layout_hdr(lrp->args.layout);
nfs_iput_and_deactive(lrp->inode);
+ put_cred(lrp->cred);
kfree(calldata);
dprintk("<-- %s\n", __func__);
}
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 84029c9b2b1b..f2dc35c22964 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1144,6 +1144,7 @@ void pnfs_layoutreturn_free_lsegs(struct pnfs_layout_hdr *lo,
static bool
pnfs_prepare_layoutreturn(struct pnfs_layout_hdr *lo,
nfs4_stateid *stateid,
+ const struct cred **cred,
enum pnfs_iomode *iomode)
{
/* Serialise LAYOUTGET/LAYOUTRETURN */
@@ -1154,18 +1155,17 @@ pnfs_prepare_layoutreturn(struct pnfs_layout_hdr *lo,
set_bit(NFS_LAYOUT_RETURN, &lo->plh_flags);
pnfs_get_layout_hdr(lo);
if (test_bit(NFS_LAYOUT_RETURN_REQUESTED, &lo->plh_flags)) {
- if (stateid != NULL) {
- nfs4_stateid_copy(stateid, &lo->plh_stateid);
- if (lo->plh_return_seq != 0)
- stateid->seqid = cpu_to_be32(lo->plh_return_seq);
- }
+ nfs4_stateid_copy(stateid, &lo->plh_stateid);
+ *cred = get_cred(lo->plh_lc_cred);
+ if (lo->plh_return_seq != 0)
+ stateid->seqid = cpu_to_be32(lo->plh_return_seq);
if (iomode != NULL)
*iomode = lo->plh_return_iomode;
pnfs_clear_layoutreturn_info(lo);
return true;
}
- if (stateid != NULL)
- nfs4_stateid_copy(stateid, &lo->plh_stateid);
+ nfs4_stateid_copy(stateid, &lo->plh_stateid);
+ *cred = get_cred(lo->plh_lc_cred);
if (iomode != NULL)
*iomode = IOMODE_ANY;
return true;
@@ -1189,20 +1189,26 @@ pnfs_init_layoutreturn_args(struct nfs4_layoutreturn_args *args,
}

static int
-pnfs_send_layoutreturn(struct pnfs_layout_hdr *lo, const nfs4_stateid *stateid,
- enum pnfs_iomode iomode, bool sync)
+pnfs_send_layoutreturn(struct pnfs_layout_hdr *lo,
+ const nfs4_stateid *stateid,
+ const struct cred **pcred,
+ enum pnfs_iomode iomode,
+ bool sync)
{
struct inode *ino = lo->plh_inode;
struct pnfs_layoutdriver_type *ld = NFS_SERVER(ino)->pnfs_curr_ld;
struct nfs4_layoutreturn *lrp;
+ const struct cred *cred = *pcred;
int status = 0;

+ *pcred = NULL;
lrp = kzalloc(sizeof(*lrp), GFP_NOFS);
if (unlikely(lrp == NULL)) {
status = -ENOMEM;
spin_lock(&ino->i_lock);
pnfs_clear_layoutreturn_waitbit(lo);
spin_unlock(&ino->i_lock);
+ put_cred(cred);
pnfs_put_layout_hdr(lo);
goto out;
}
@@ -1210,7 +1216,7 @@ pnfs_send_layoutreturn(struct pnfs_layout_hdr *lo, const nfs4_stateid *stateid,
pnfs_init_layoutreturn_args(&lrp->args, lo, stateid, iomode);
lrp->args.ld_private = &lrp->ld_private;
lrp->clp = NFS_SERVER(ino)->nfs_client;
- lrp->cred = lo->plh_lc_cred;
+ lrp->cred = cred;
if (ld->prepare_layoutreturn)
ld->prepare_layoutreturn(&lrp->args);

@@ -1255,15 +1261,16 @@ static void pnfs_layoutreturn_before_put_layout_hdr(struct pnfs_layout_hdr *lo)
return;
spin_lock(&inode->i_lock);
if (pnfs_layout_need_return(lo)) {
+ const struct cred *cred;
nfs4_stateid stateid;
enum pnfs_iomode iomode;
bool send;

- send = pnfs_prepare_layoutreturn(lo, &stateid, &iomode);
+ send = pnfs_prepare_layoutreturn(lo, &stateid, &cred, &iomode);
spin_unlock(&inode->i_lock);
if (send) {
/* Send an async layoutreturn so we dont deadlock */
- pnfs_send_layoutreturn(lo, &stateid, iomode, false);
+ pnfs_send_layoutreturn(lo, &stateid, &cred, iomode, false);
}
} else
spin_unlock(&inode->i_lock);
@@ -1283,6 +1290,7 @@ _pnfs_return_layout(struct inode *ino)
struct pnfs_layout_hdr *lo = NULL;
struct nfs_inode *nfsi = NFS_I(ino);
LIST_HEAD(tmp_list);
+ const struct cred *cred;
nfs4_stateid stateid;
int status = 0;
bool send, valid_layout;
@@ -1327,10 +1335,10 @@ _pnfs_return_layout(struct inode *ino)
goto out_put_layout_hdr;
}

- send = pnfs_prepare_layoutreturn(lo, &stateid, NULL);
+ send = pnfs_prepare_layoutreturn(lo, &stateid, &cred, NULL);
spin_unlock(&ino->i_lock);
if (send)
- status = pnfs_send_layoutreturn(lo, &stateid, IOMODE_ANY, true);
+ status = pnfs_send_layoutreturn(lo, &stateid, &cred, IOMODE_ANY, true);
out_put_layout_hdr:
pnfs_free_lseg_list(&tmp_list);
pnfs_put_layout_hdr(lo);
@@ -1376,6 +1384,7 @@ bool pnfs_roc(struct inode *ino,
struct nfs4_state *state;
struct pnfs_layout_hdr *lo;
struct pnfs_layout_segment *lseg, *next;
+ const struct cred *lc_cred;
nfs4_stateid stateid;
enum pnfs_iomode iomode = 0;
bool layoutreturn = false, roc = false;
@@ -1445,16 +1454,20 @@ bool pnfs_roc(struct inode *ino,
* 2. we don't send layoutreturn
*/
/* lo ref dropped in pnfs_roc_release() */
- layoutreturn = pnfs_prepare_layoutreturn(lo, &stateid, &iomode);
+ layoutreturn = pnfs_prepare_layoutreturn(lo, &stateid, &lc_cred, &iomode);
/* If the creds don't match, we can't compound the layoutreturn */
- if (!layoutreturn || cred_fscmp(cred, lo->plh_lc_cred) != 0)
+ if (!layoutreturn)
goto out_noroc;
+ if (cred_fscmp(cred, lc_cred) != 0)
+ goto out_noroc_put_cred;

roc = layoutreturn;
pnfs_init_layoutreturn_args(args, lo, &stateid, iomode);
res->lrs_present = 0;
layoutreturn = false;

+out_noroc_put_cred:
+ put_cred(lc_cred);
out_noroc:
spin_unlock(&ino->i_lock);
rcu_read_unlock();
@@ -1467,7 +1480,7 @@ bool pnfs_roc(struct inode *ino,
return true;
}
if (layoutreturn)
- pnfs_send_layoutreturn(lo, &stateid, iomode, true);
+ pnfs_send_layoutreturn(lo, &stateid, &lc_cred, iomode, true);
pnfs_put_layout_hdr(lo);
return false;
}
@@ -2464,13 +2477,14 @@ pnfs_mark_layout_for_return(struct inode *inode,
* for how it works.
*/
if (pnfs_mark_matching_lsegs_return(lo, &lo->plh_return_segs, range, 0) != -EBUSY) {
+ const struct cred *cred;
nfs4_stateid stateid;
enum pnfs_iomode iomode;

- return_now = pnfs_prepare_layoutreturn(lo, &stateid, &iomode);
+ return_now = pnfs_prepare_layoutreturn(lo, &stateid, &cred, &iomode);
spin_unlock(&inode->i_lock);
if (return_now)
- pnfs_send_layoutreturn(lo, &stateid, iomode, false);
+ pnfs_send_layoutreturn(lo, &stateid, &cred, iomode, false);
} else {
spin_unlock(&inode->i_lock);
nfs_commit_inode(inode, 0);
--
2.25.1